for the past couple of releases of Hadoop 2.X code line the issueof integration between Hadoop and its downstream projects hasbecome quite a thorny issue. The poster child here is Oozie, whereevery release of Hadoop 2.X seems to be breaking the compatibilityin various unpredictable ways. At times other components (suchas HBase for example) also seem to be affected.

Now, to be extremely clear -- I'm NOT talking about the *latest* versionof Oozie working with the *latest* version of Hadoop, insteadmy observations come from running previous *stable* releasesof Bigtop on top of Hadoop 2.X RCs.

As many of you know Apache Bigtop aims at providing a singleplatform for integration of Hadoop and Hadoop ecosystem projects.As such we're uniquely positioned to track compatibility betweendifferent Hadoop releases with regards to the downstream components(things like Oozie, Pig, Hive, Mahout, etc.). Every single single RCwe've been pretty diligent at trying to provide integration-level feedbackon the quality of the upcoming release, but it seems that our effortsdon't quite suffice in Hadoop 2.X stabilizing.

Of course, one could argue that while Hadoop 2.X code line wasdesignated 'alpha' expecting much in the way of perfect integrationand compatibility was NOT what the Hadoop community wasfocusing on. I can appreciate that view, but what I'm interested inis the future of Hadoop 2.X not its past. Hence, here's my questionto all of you as a Hadoop community at large:

Do you guys think that the project have reached a point where integrationand compatibility issues should be prioritized really high on the listof things that make or break each future release?

The good news, is that Bigtop's charter is in big part *exactly* aboutproviding you with this kind of feedback. We can easily tell you whenHadoop behavior, with regard to downstream components, changesbetween a previous stable release and the new RC (or even branch/trunk).What we can NOT do is submit patches for all the issues. We are simplytoo small a project and we need your help with that.

I truly believe that we owe it to the downstream projects, and in thesecond half of this email I will try to convince you of that.

We all know that integration projects are impossible to pull offunless there's a general consensus between all of the projects involvedthat they indeed need to work with each other. You can NOT forcethat notion, but you can always try to influence. This relationshipgoes both ways.

Consider a question in front of the downstream communitiesof whether or not to adopt Hadoop 2.X as the basis. To answerthat question each downstream project has to be reasonablysure that their concerns will NOT fall on deaf ears and thatHadoop developers are, essentially, 'ready' for them to pickup Hadoop 2.X. I would argue that so far the Hadoop communityhad gone out of its way to signal that 2.X codeline is NOTready for the downstream.

I would argue that moving forward this is a really unfortunatesituation that may end up undermining the long term successof Hadoop 2.X if we don't start addressing the problem. Thinkabout it -- 90% of unit tests that run downstream on Apacheinfrastructure are still exercising Hadoop 1.X underneath.In fact, if you were to forcefully make, lets say, HBase'sunit tests run on top of Hadoop 2.X quite a few of themare going to fail. Hadoop community is, in effect, cuttingitself off from the biggest source of feedback -- its downstreamusers. This in turn:

* leaves Hadoop project in a perpetual state of broken windows syndrome.

* leaves Apache Hadoop 2.X releases in a state considerably inferior to the releases *including* Apache Hadoop done by the vendors. The users have no choice but to alight themselves with vendor offerings if they wish to utilize latest Hadoop functionality. The artifact that is know as Apache Hadoop 2.X stopped being a viable choice thus fracturing the user community and reducing the benefits of a commonly deployed codebase.

* leaves downstream projects of Hadoop in a jaded state where they legitimately get very discouraged and frustrated and eventually give up thinking that -- well, we work with one release of Hadoop (the stable one Hadoop 1.X) and we shall wait for the Hadoop community to get their act together.

In my view (shared by quite a few members of the Apache Bigtop) wecan definitely do better than this if we all agree that the proposedfirst 'beta' release of Hadoop 2.0.4 is the right time for it to happen.

It is about time Hadoop 2.X community wins back all those end usersand downstream projects that got left behind during the alphastabilization phase.

for the past couple of releases of Hadoop 2.X code line the issueof integration between Hadoop and its downstream projects hasbecome quite a thorny issue. The poster child here is Oozie, whereevery release of Hadoop 2.X seems to be breaking the compatibilityin various unpredictable ways. At times other components (suchas HBase for example) also seem to be affected.

Now, to be extremely clear -- I'm NOT talking about the *latest* versionof Oozie working with the *latest* version of Hadoop, insteadmy observations come from running previous *stable* releasesof Bigtop on top of Hadoop 2.X RCs.

As many of you know Apache Bigtop aims at providing a singleplatform for integration of Hadoop and Hadoop ecosystem projects.As such we're uniquely positioned to track compatibility betweendifferent Hadoop releases with regards to the downstream components(things like Oozie, Pig, Hive, Mahout, etc.). Every single single RCwe've been pretty diligent at trying to provide integration-level feedbackon the quality of the upcoming release, but it seems that our effortsdon't quite suffice in Hadoop 2.X stabilizing.

Of course, one could argue that while Hadoop 2.X code line wasdesignated 'alpha' expecting much in the way of perfect integrationand compatibility was NOT what the Hadoop community wasfocusing on. I can appreciate that view, but what I'm interested inis the future of Hadoop 2.X not its past. Hence, here's my questionto all of you as a Hadoop community at large:

Do you guys think that the project have reached a point where integrationand compatibility issues should be prioritized really high on the listof things that make or break each future release?

The good news, is that Bigtop's charter is in big part *exactly* aboutproviding you with this kind of feedback. We can easily tell you whenHadoop behavior, with regard to downstream components, changesbetween a previous stable release and the new RC (or even branch/trunk).What we can NOT do is submit patches for all the issues. We are simplytoo small a project and we need your help with that.

I truly believe that we owe it to the downstream projects, and in thesecond half of this email I will try to convince you of that.

We all know that integration projects are impossible to pull offunless there's a general consensus between all of the projects involvedthat they indeed need to work with each other. You can NOT forcethat notion, but you can always try to influence. This relationshipgoes both ways.

Consider a question in front of the downstream communitiesof whether or not to adopt Hadoop 2.X as the basis. To answerthat question each downstream project has to be reasonablysure that their concerns will NOT fall on deaf ears and thatHadoop developers are, essentially, 'ready' for them to pickup Hadoop 2.X. I would argue that so far the Hadoop communityhad gone out of its way to signal that 2.X codeline is NOTready for the downstream.

I would argue that moving forward this is a really unfortunatesituation that may end up undermining the long term successof Hadoop 2.X if we don't start addressing the problem. Thinkabout it -- 90% of unit tests that run downstream on Apacheinfrastructure are still exercising Hadoop 1.X underneath.In fact, if you were to forcefully make, lets say, HBase'sunit tests run on top of Hadoop 2.X quite a few of themare going to fail. Hadoop community is, in effect, cuttingitself off from the biggest source of feedback -- its downstreamusers. This in turn:

* leaves Hadoop project in a perpetual state of broken windows syndrome.

* leaves Apache Hadoop 2.X releases in a state considerably inferior to the releases *including* Apache Hadoop done by the vendors. The users have no choice but to alight themselves with vendor offerings if they wish to utilize latest Hadoop functionality. The artifact that is know as Apache Hadoop 2.X stopped being a viable choice thus fracturing the user community and reducing the benefits of a commonly deployed codebase.

* leaves downstream projects of Hadoop in a jaded state where they legitimately get very discouraged and frustrated and eventually give up thinking that -- well, we work with one release of Hadoop (the stable one Hadoop 1.X) and we shall wait for the Hadoop community to get their act together.

In my view (shared by quite a few members of the Apache Bigtop) wecan definitely do better than this if we all agree that the proposedfirst 'beta' release of Hadoop 2.0.4 is the right time for it to happen.

It is about time Hadoop 2.X community wins back all those end usersand downstream projects that got left behind during the alphastabilization phase.

Integration is high on the list of *every* release. In future, if anyone or bigtop wants to help, running integration tests on a hadoop RC and providing feedback would be very welcome. I'm pretty sure I will stop an RC if it means it breaks and Oozie or HBase or Pig or Hive and re-spin it. For e.g. see recent efforts to do a 2.0.4-alpha.

With hadoop-2.0.3-alpha we discovered 3 *bugs* - making it sound like we intentionally disregard integation issues is very harsh.

Please also see other thread where we discussed stabilizing APIS, protocols etc. for the next 'beta' release.

Arun

On Feb 26, 2013, at 5:43 PM, Roman Shaposhnik wrote:

> Hi!> > for the past couple of releases of Hadoop 2.X code line the issue> of integration between Hadoop and its downstream projects has> become quite a thorny issue. The poster child here is Oozie, where> every release of Hadoop 2.X seems to be breaking the compatibility> in various unpredictable ways. At times other components (such> as HBase for example) also seem to be affected.> > Now, to be extremely clear -- I'm NOT talking about the *latest* version> of Oozie working with the *latest* version of Hadoop, instead> my observations come from running previous *stable* releases> of Bigtop on top of Hadoop 2.X RCs.> > As many of you know Apache Bigtop aims at providing a single> platform for integration of Hadoop and Hadoop ecosystem projects.> As such we're uniquely positioned to track compatibility between> different Hadoop releases with regards to the downstream components> (things like Oozie, Pig, Hive, Mahout, etc.). Every single single RC> we've been pretty diligent at trying to provide integration-level feedback> on the quality of the upcoming release, but it seems that our efforts> don't quite suffice in Hadoop 2.X stabilizing.> > Of course, one could argue that while Hadoop 2.X code line was> designated 'alpha' expecting much in the way of perfect integration> and compatibility was NOT what the Hadoop community was> focusing on. I can appreciate that view, but what I'm interested in> is the future of Hadoop 2.X not its past. Hence, here's my question> to all of you as a Hadoop community at large:> > Do you guys think that the project have reached a point where integration> and compatibility issues should be prioritized really high on the list> of things that make or break each future release?> > The good news, is that Bigtop's charter is in big part *exactly* about> providing you with this kind of feedback. We can easily tell you when> Hadoop behavior, with regard to downstream components, changes> between a previous stable release and the new RC (or even branch/trunk).> What we can NOT do is submit patches for all the issues. We are simply> too small a project and we need your help with that.> > I truly believe that we owe it to the downstream projects, and in the> second half of this email I will try to convince you of that.> > We all know that integration projects are impossible to pull off> unless there's a general consensus between all of the projects involved> that they indeed need to work with each other. You can NOT force> that notion, but you can always try to influence. This relationship> goes both ways.> > Consider a question in front of the downstream communities> of whether or not to adopt Hadoop 2.X as the basis. To answer> that question each downstream project has to be reasonably> sure that their concerns will NOT fall on deaf ears and that> Hadoop developers are, essentially, 'ready' for them to pick> up Hadoop 2.X. I would argue that so far the Hadoop community> had gone out of its way to signal that 2.X codeline is NOT> ready for the downstream.> > I would argue that moving forward this is a really unfortunate> situation that may end up undermining the long term success> of Hadoop 2.X if we don't start addressing the problem. Think> about it -- 90% of unit tests that run downstream on Apache

first of all, I don't think anyone is trying to put a blame on someoneelse. E.g. I had similar experience with Oozie being broken because ofcertain released changes in the upstream.

I am sure that most people in BigTop community - especially those whoshare the committer-ship privilege in BigTop and other upstreamprojects, including Hadoop, - would be happy to help with thestabilization of the Hadoop base. The issue that a downstreamintegration project is likely to have is - for once - the absence ofregularly published development artifacts. In the light of "it didn'thappen if there's no picture" here's a couple of examples:

- 2.0.2-SNAPSHOT weren't published at all; only release 2.0.2-alpha artifacts were - 2.0.3-SNAPSHOT weren't published until Feb 29, 2013 (it happened just once)

So, technically speaking, unless an integration project is willing tobuild and maintain its own artifacts, it is impossible to do anypreventive validation.

Which brings me to my next question: how do you guys address"Integration is high on the list of *every* release". Again, pleasedon't get me wrong - I am not looking to lay a blame on or corneranyone - I am really curious and would appreciate the input.Vinod:

> As you yourself noted later, the pain is part of the 'alpha' status> of the release. We are targeting +one of the immediate future> releases to be a beta and so these troubles are really only the> short +term.

I don't really want to get into the discussion about of whatconstitutes the alpha and how it has delayed the adoption of Hadoop2line. However, I want to point out that it is especially important for"alpha" platform to work nicely with downstream consumers of the saidplatform. For quite obvious reasons, I believe.

> I think there is a fundamental problem with the interaction of> Bigtop with the downstream projects, if nothing else, with

BigTop is as downstream as it can get, because BigTop essentiallyconsumes all other component releases in order to produce a viablestack. Technicalities aside...

> Hadoop. We never formalized on the process, will BigTop step in> after an RC is up for vote or before? As I see it, it's happening

Bigtop essentially can give any component, including Hadoop, andbetter yet - the set of components - certain guaratees aboutcompatibility and dependencies being included. Case in point ismissing commons libraries missed in 1.0.1 release that essentiallyprevented HBase from working properly.

> after the vote is up, so no wonder we are in this state. Shall we> have a pre-notice to Bigtop so that it can step in before?

The above is in contradiction with earlier statement of "Integrationis high on the list of *every* release". If BigTop isn't used forintegration testing, then how said integration testing is performed?Is it some sort of test-patch process as Luke referred earlier? Andwhy it leaves the room for the integration issues being uncaught?Again, I am genuinely interested to know.

> these short term pains. I'd rather like us swim through these now> instead of support broken APIs and features in our beta, having seen> this very thing happen with 1.*.

I think you're mixing the point of integration with downstream andbeing in an alpha phase of the development. The former isn't aboutsupporting "broken APIs" - it is about being consistent and avoidbreaking the downstream applicaitons without letting said applicationsto accomodate the platform changes first.

Changes in the API, after all, can be relatively easy traced byintegration validation - this is the whole point of integrationtesting. And BigTop does the job better then anything around, simplybecause there's nothing else around to do it.

If you stay in shape-shifting "alpha" that doesn't integrate well fora very long time, you risk to lose downstream customers' interest,because they might get tired of waiting until a next stable API willbe ready for them.

> Let's fix the way the release related communication is happening

This is a very good point indeed! Let's start a separate discussionthread on how we can improve the release model for coming Hadoopreleases, where we - as the community - can provide better guaranteesof the inter-component compatibility (sorry for an overused word).

Don't let the name fool you, it publishes not just common, but HDFS, YARN,MR, and tools too. You should now have branch-2 SNAPSHOTS updated on eachcommit to branch-2. Feel free to bug me if you need more integrationpoints. I am not an RE guy, but I can hack it to make things work :)

--Bobby

On 3/5/13 12:15 AM, "Konstantin Boudnik" <[EMAIL PROTECTED]> wrote:

>Arun,>>first of all, I don't think anyone is trying to put a blame on someone>else. E.g. I had similar experience with Oozie being broken because of>certain released changes in the upstream.>>I am sure that most people in BigTop community - especially those who>share the committer-ship privilege in BigTop and other upstream>projects, including Hadoop, - would be happy to help with the>stabilization of the Hadoop base. The issue that a downstream>integration project is likely to have is - for once - the absence of>regularly published development artifacts. In the light of "it didn't>happen if there's no picture" here's a couple of examples:>> - 2.0.2-SNAPSHOT weren't published at all; only release 2.0.2-alpha>artifacts were> - 2.0.3-SNAPSHOT weren't published until Feb 29, 2013 (it happened just>once)>>So, technically speaking, unless an integration project is willing to>build and maintain its own artifacts, it is impossible to do any>preventive validation.>>Which brings me to my next question: how do you guys address>"Integration is high on the list of *every* release". Again, please>don't get me wrong - I am not looking to lay a blame on or corner>anyone - I am really curious and would appreciate the input.>>>Vinod:>>> As you yourself noted later, the pain is part of the 'alpha' status>> of the release. We are targeting +one of the immediate future>> releases to be a beta and so these troubles are really only the>> short +term.>>I don't really want to get into the discussion about of what>constitutes the alpha and how it has delayed the adoption of Hadoop2>line. However, I want to point out that it is especially important for>"alpha" platform to work nicely with downstream consumers of the said>platform. For quite obvious reasons, I believe.>>> I think there is a fundamental problem with the interaction of>> Bigtop with the downstream projects, if nothing else, with>>BigTop is as downstream as it can get, because BigTop essentially>consumes all other component releases in order to produce a viable>stack. Technicalities aside...>>> Hadoop. We never formalized on the process, will BigTop step in>> after an RC is up for vote or before? As I see it, it's happening>>Bigtop essentially can give any component, including Hadoop, and>better yet - the set of components - certain guaratees about>compatibility and dependencies being included. Case in point is>missing commons libraries missed in 1.0.1 release that essentially>prevented HBase from working properly.>>> after the vote is up, so no wonder we are in this state. Shall we>> have a pre-notice to Bigtop so that it can step in before?>>The above is in contradiction with earlier statement of "Integration>is high on the list of *every* release". If BigTop isn't used for>integration testing, then how said integration testing is performed?>Is it some sort of test-patch process as Luke referred earlier? And>why it leaves the room for the integration issues being uncaught?>Again, I am genuinely interested to know.>>> these short term pains. I'd rather like us swim through these now>> instead of support broken APIs and features in our beta, having seen>> this very thing happen with 1.*.>>I think you're mixing the point of integration with downstream and>being in an alpha phase of the development. The former isn't about>supporting "broken APIs" - it is about being consistent and avoid

Great start, Bobby! I certainly can jump on fix something quickly if needed aswell (neither an RE person, but CI is truly a dev. tool!)

Thanks! Cos

On Tue, Mar 05, 2013 at 07:18AM, Robert Evans wrote:> That is a great point. I have been meaning to set up the Jenkins build> for branch-2 for a while, so I took the 10 mins and just did it.> > https://builds.apache.org/job/Hadoop-Common-2-Commit/> > Don't let the name fool you, it publishes not just common, but HDFS, YARN,> MR, and tools too. You should now have branch-2 SNAPSHOTS updated on each> commit to branch-2. Feel free to bug me if you need more integration> points. I am not an RE guy, but I can hack it to make things work :)> > --Bobby> > On 3/5/13 12:15 AM, "Konstantin Boudnik" <[EMAIL PROTECTED]> wrote:> > >Arun,> >> >first of all, I don't think anyone is trying to put a blame on someone> >else. E.g. I had similar experience with Oozie being broken because of> >certain released changes in the upstream.> >> >I am sure that most people in BigTop community - especially those who> >share the committer-ship privilege in BigTop and other upstream> >projects, including Hadoop, - would be happy to help with the> >stabilization of the Hadoop base. The issue that a downstream> >integration project is likely to have is - for once - the absence of> >regularly published development artifacts. In the light of "it didn't> >happen if there's no picture" here's a couple of examples:> >> > - 2.0.2-SNAPSHOT weren't published at all; only release 2.0.2-alpha> >artifacts were> > - 2.0.3-SNAPSHOT weren't published until Feb 29, 2013 (it happened just> >once)> >> >So, technically speaking, unless an integration project is willing to> >build and maintain its own artifacts, it is impossible to do any> >preventive validation.> >> >Which brings me to my next question: how do you guys address> >"Integration is high on the list of *every* release". Again, please> >don't get me wrong - I am not looking to lay a blame on or corner> >anyone - I am really curious and would appreciate the input.> >> >> >Vinod:> >> >> As you yourself noted later, the pain is part of the 'alpha' status> >> of the release. We are targeting +one of the immediate future> >> releases to be a beta and so these troubles are really only the> >> short +term.> >> >I don't really want to get into the discussion about of what> >constitutes the alpha and how it has delayed the adoption of Hadoop2> >line. However, I want to point out that it is especially important for> >"alpha" platform to work nicely with downstream consumers of the said> >platform. For quite obvious reasons, I believe.> >> >> I think there is a fundamental problem with the interaction of> >> Bigtop with the downstream projects, if nothing else, with> >> >BigTop is as downstream as it can get, because BigTop essentially> >consumes all other component releases in order to produce a viable> >stack. Technicalities aside...> >> >> Hadoop. We never formalized on the process, will BigTop step in> >> after an RC is up for vote or before? As I see it, it's happening> >> >Bigtop essentially can give any component, including Hadoop, and> >better yet - the set of components - certain guaratees about> >compatibility and dependencies being included. Case in point is> >missing commons libraries missed in 1.0.1 release that essentially> >prevented HBase from working properly.> >> >> after the vote is up, so no wonder we are in this state. Shall we> >> have a pre-notice to Bigtop so that it can step in before?> >> >The above is in contradiction with earlier statement of "Integration> >is high on the list of *every* release". If BigTop isn't used for> >integration testing, then how said integration testing is performed?> >Is it some sort of test-patch process as Luke referred earlier? And> >why it leaves the room for the integration issues being uncaught?> >Again, I am genuinely interested to know.

> Great start, Bobby! I certainly can jump on fix something quickly if> needed as> well (neither an RE person, but CI is truly a dev. tool!)>> Thanks!> Cos>> On Tue, Mar 05, 2013 at 07:18AM, Robert Evans wrote:> > That is a great point. I have been meaning to set up the Jenkins build> > for branch-2 for a while, so I took the 10 mins and just did it.> >> > https://builds.apache.org/job/Hadoop-Common-2-Commit/> >> > Don't let the name fool you, it publishes not just common, but HDFS,> YARN,> > MR, and tools too. You should now have branch-2 SNAPSHOTS updated on> each> > commit to branch-2. Feel free to bug me if you need more integration> > points. I am not an RE guy, but I can hack it to make things work :)> >> > --Bobby> >> > On 3/5/13 12:15 AM, "Konstantin Boudnik" <[EMAIL PROTECTED]> wrote:> >> > >Arun,> > >> > >first of all, I don't think anyone is trying to put a blame on someone> > >else. E.g. I had similar experience with Oozie being broken because of> > >certain released changes in the upstream.> > >> > >I am sure that most people in BigTop community - especially those who> > >share the committer-ship privilege in BigTop and other upstream> > >projects, including Hadoop, - would be happy to help with the> > >stabilization of the Hadoop base. The issue that a downstream> > >integration project is likely to have is - for once - the absence of> > >regularly published development artifacts. In the light of "it didn't> > >happen if there's no picture" here's a couple of examples:> > >> > > - 2.0.2-SNAPSHOT weren't published at all; only release 2.0.2-alpha> > >artifacts were> > > - 2.0.3-SNAPSHOT weren't published until Feb 29, 2013 (it happened> just> > >once)> > >> > >So, technically speaking, unless an integration project is willing to> > >build and maintain its own artifacts, it is impossible to do any> > >preventive validation.> > >> > >Which brings me to my next question: how do you guys address> > >"Integration is high on the list of *every* release". Again, please> > >don't get me wrong - I am not looking to lay a blame on or corner> > >anyone - I am really curious and would appreciate the input.> > >> > >> > >Vinod:> > >> > >> As you yourself noted later, the pain is part of the 'alpha' status> > >> of the release. We are targeting +one of the immediate future> > >> releases to be a beta and so these troubles are really only the> > >> short +term.> > >> > >I don't really want to get into the discussion about of what> > >constitutes the alpha and how it has delayed the adoption of Hadoop2> > >line. However, I want to point out that it is especially important for> > >"alpha" platform to work nicely with downstream consumers of the said> > >platform. For quite obvious reasons, I believe.> > >> > >> I think there is a fundamental problem with the interaction of> > >> Bigtop with the downstream projects, if nothing else, with> > >> > >BigTop is as downstream as it can get, because BigTop essentially> > >consumes all other component releases in order to produce a viable> > >stack. Technicalities aside...> > >> > >> Hadoop. We never formalized on the process, will BigTop step in> > >> after an RC is up for vote or before? As I see it, it's happening> > >> > >Bigtop essentially can give any component, including Hadoop, and> > >better yet - the set of components - certain guaratees about> > >compatibility and dependencies being included. Case in point is> > >missing commons libraries missed in 1.0.1 release that essentially> > >prevented HBase from working properly.> > >> > >> after the vote is up, so no wonder we are in this state. Shall we> > >> have a pre-notice to Bigtop so that it can step in before?

> The issue that a downstream> integration project is likely to have is - for once - the absence of> regularly published development artifacts. In the light of "it didn't> happen if there's no picture" here's a couple of examples:

On Wed, Mar 06, 2013 at 07:24AM, Arun C Murthy wrote:> Cos,> > On Mar 4, 2013, at 10:15 PM, Konstantin Boudnik wrote:> > > The issue that a downstream> > integration project is likely to have is - for once - the absence of> > regularly published development artifacts. In the light of "it didn't> > happen if there's no picture" here's a couple of examples:> > Maybe I wasn't clear, apologies, my request is simpler: Can Bigtop validate a Hadoop RC?

No offense taken. I think this is indeed the intention of initial andfollow-up emails. There need to be a bit more coordination between thetwo, so BigTop's branches can be set in advance to churn stack buildsand validations with underlying Hadoop RCs or even before; and HadoopRM - and potentially downstream components - have more time to reactto the problems.

One of the issues here is a difference in the release schedule betweenthe two. Perhaps we can setup a validation branch in the bigtop tohelp with releases. This is something that needs to be decided withinthe project apparently, but the it might work.

Cos

> Every RC has it's artifacts in staging at the ASF maven repo. In the past we have had Bigtop actually verifying an RC:> http://s.apache.org/sjz> > If Bigtop can do that consistently, it would definitely help. Agree?> > thanks,> Arun>

On Wed, Mar 6, 2013 at 7:24 AM, Arun C Murthy <[EMAIL PROTECTED]> wrote:>> The issue that a downstream>> integration project is likely to have is - for once - the absence of>> regularly published development artifacts. In the light of "it didn't>> happen if there's no picture" here's a couple of examples:>> Maybe I wasn't clear, apologies, my request is simpler: Can Bigtop validate a Hadoop RC?

The short answer to this is -- yes. It would be extremely nice ifwe don't have to wait till the first official RC but could jump onthe branch somewhat sooner. That, of course, would requirea higher degree of coordination. If future Hadoop RMs wouldbe willing to drop us a note and indicate when the branchis in a shape where Bigtop feedback is ready to be receivedI think that'll be the best way to proceed.

Do you think this would be a reasonable agreement?

On a related subject -- it would be extremely nice if Hadoopcommunity can help us with planning the bill of materialsfor the future release of Bigtop. Essentially taking a bitof a more active role in yay'ing or nay'ing our versionchoices. There's a thread on LTS Bigtop releases thatCos started but I think we can only hope to have an LTSif the underlying Hadoop is also LTS'ish.

>> If future Hadoop RMs would> be willing to drop us a note and indicate when the branch> is in a shape where Bigtop feedback is ready to be received> I think that'll be the best way to proceed.This info is always broadcast to [EMAIL PROTECTED],but I will try to remember to send such a pre-announcement directlyto Bigtop also. In fact, I'll modify the HowToRelease instructions toincorporate this as a step.

> On Wed, Mar 6, 2013 at 7:24 AM, Arun C Murthy <[EMAIL PROTECTED]> wrote:> >> The issue that a downstream> >> integration project is likely to have is - for once - the absence of> >> regularly published development artifacts. In the light of "it didn't> >> happen if there's no picture" here's a couple of examples:> >> > Maybe I wasn't clear, apologies, my request is simpler: Can Bigtop> validate a Hadoop RC?>> The short answer to this is -- yes. It would be extremely nice if> we don't have to wait till the first official RC but could jump on> the branch somewhat sooner. That, of course, would require> a higher degree of coordination. If future Hadoop RMs would> be willing to drop us a note and indicate when the branch> is in a shape where Bigtop feedback is ready to be received> I think that'll be the best way to proceed.>> Do you think this would be a reasonable agreement?>> On a related subject -- it would be extremely nice if Hadoop> community can help us with planning the bill of materials> for the future release of Bigtop. Essentially taking a bit> of a more active role in yay'ing or nay'ing our version> choices. There's a thread on LTS Bigtop releases that> Cos started but I think we can only hope to have an LTS> if the underlying Hadoop is also LTS'ish.>> Thanks,> Roman.>

Replies inline.> for the past couple of releases of Hadoop 2.X code line the issue> of integration between Hadoop and its downstream projects has> become quite a thorny issue. The poster child here is Oozie, where> every release of Hadoop 2.X seems to be breaking the compatibility> in various unpredictable ways. At times other components (such> as HBase for example) also seem to be affected.> > Now, to be extremely clear -- I'm NOT talking about the *latest* version> of Oozie working with the *latest* version of Hadoop, instead> my observations come from running previous *stable* releases> of Bigtop on top of Hadoop 2.X RCs.As you yourself noted later, the pain is part of the 'alpha' status of the release. We are targeting one of the immediate future releases to be a beta and so these troubles are really only the short term.> Do you guys think that the project have reached a point where integration> and compatibility issues should be prioritized really high on the list> of things that make or break each future release?You should see the other discussion where we discussed about this very question of stability of our immediate future releases.> The good news, is that Bigtop's charter is in big part *exactly* about> providing you with this kind of feedback. We can easily tell you when> Hadoop behavior, with regard to downstream components, changes> between a previous stable release and the new RC (or even branch/trunk).> What we can NOT do is submit patches for all the issues. We are simply> too small a project and we need your help with that.I think there is a fundamental problem with the interaction of Bigtop with the downstream projects, if nothing else, with Hadoop. We never formalized on the process, will BigTop step in after an RC is up for vote or before? As I see it, it's happening after the vote is up, so no wonder we are in this state. Shall we have a pre-notice to Bigtop so that it can step in before?> I would argue that moving forward this is a really unfortunate> situation that may end up undermining the long term success> of Hadoop 2.X if we don't start addressing the problem. Think> about it -- 90% of unit tests that run downstream on Apache> infrastructure are still exercising Hadoop 1.X underneath.> In fact, if you were to forcefully make, lets say, HBase's> unit tests run on top of Hadoop 2.X quite a few of them> are going to fail. Hadoop community is, in effect, cutting> itself off from the biggest source of feedback -- its downstream> users. This in turn:> > * leaves Hadoop project in a perpetual state of broken> windows syndrome.> > * leaves Apache Hadoop 2.X releases in a state considerably> inferior to the releases *including* Apache Hadoop done by the> vendors. The users have no choice but to alight themselves> with vendor offerings if they wish to utilize latest Hadoop functionality.> The artifact that is know as Apache Hadoop 2.X stopped being> a viable choice thus fracturing the user community and reducing> the benefits of a commonly deployed codebase.> > * leaves downstream projects of Hadoop in a jaded state where> they legitimately get very discouraged and frustrated and eventually> give up thinking that -- well, we work with one release of Hadoop> (the stable one Hadoop 1.X) and we shall wait for the Hadoop> community to get their act together.> > It is about time Hadoop 2.X community wins back all those end users> and downstream projects that got left behind during the alpha> stabilization phase.This is overblown, we've been working with various downstream projects - Hbase, Hive, Pig, Oozie to help them transition them to 2.x and I believe we've made significant progress already.

Sure enough, there are continuing pains, but these are part of the alpha status. If we are really looking forward to a stable release which can support going forward, we need to live with and dive past these short term pains. I'd rather like us swim through these now instead of support broken APIs and features in our beta, having seen this very thing happen with 1.*.

Let's fix the way the release related communication is happening across our projects so that we can all work together and make 2.X a success.

Thanks,+Vinod

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Vinod Kumar Vavilapalli 2013-03-01, 20:23

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